International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

To reduce the sintering temperature in the microstructural design of α-Al2O3-based ceramics, a mixture of basalt glass and yttria-stabilized zirconia (YSZ) was used. The effect of isothermal holding time during liquid-phase sintering of a composite containing 85 wt.% α-Al2O3 and 15 wt.% (basalt glass + YSZ) on its mechanical properties was investigated. The samples were sintered at temperatures of 1450 and 1500 °C for 2–6 hours. It was established that sintering occurs in the presence of a liquid phase that persists throughout the entire holding period, and the densification of the material is determined by the rearrangement and Ostwald ripening processes of Al2O3 grains. The maximum hardness reached 7.73 GPa, while the fracture toughness reached 7.95 MPa•m¹ᐟ². The effect of microstructural evolution on the hardness and fracture toughness of the composite was demonstrated.

The results of investigations of basic physical and chemical properties for aluminosilicate melts of different compositionsis presented. It is shown that the highest values of surface tension and adhesion was observed for the basalt melts, whereas neutral aluminosilicate glass melts without iron oxides in their composition are characterized by a high value of contact angle and the lowest values of surface forces. The insertion in the melt of ZrO₂ increases significantly wetting angles, surface tension and adhesion throughout the temperature range as compared with the same melts without zirconia. Basalt melts differ by lower viscosities and significantly less sensitivity to the effects of additives on viscosity of zirconium oxide as compared to the andesite-basalt melts.